Sunday, July 3, 2022

Heifers coming in light

Concern is being expressed by many in the dairy industry about underweight dairy heifers entering herds and the effect this is having on herd performance. Livestock Improvement Corporation (LIC) is raising awareness about the issue after a study of 28,271 animals born in 2007 showed 35% did not record a third calving. In the study of the 2007-born animals, 15% didn’t record a second calving. LIC’s Greg McNeil estimates the loss of production and reproductive performance because of animals being below target weights is costing the dairy industry around $100 million annually.

He explains that when heifers go into their first mating underweight they are slower to cycle, their social interactions are compromised, and they are still trying to grow.

Heifers 10% below their target liveweight have a 5% drop-off in their six-week in-calf rate and a 2% increase in empty rate. They also produce less – around 10kg MS over their first lactation – and have poorer on-going reproductive performance.

LIC genetics consultant Jack Hooper says the dairy industry has undergone some significant changes in recent years but there is now more of a focus on cow productivity. A feature of this focus is the size of the two-year-olds when they enter the herd and their subsequent performance.

Greg McNeil estimates that animals below target weights are costing the dairy industry $100 million annually.

“Dairy farmers want to have youngsters entering the herd in better condition and at liveweight targets while graziers are seeing this as a challenge and one they want to respond to.”

McNeil and Hooper believe the poor feeding being highlighted in the LIC data is a result of a number of factors including feed quality, incorrect allocation and the integration of dairy grazers into existing farm systems.

It is often a question of which class of livestock is getting the priority feed, McNeil says.

“Dairy animals are like bull beef in that they need to grow every day.

“Every day they are not growing is a day they need to make up for.”

Hooper explains that merely maintaining heifers over winter in the hope they will experience compensatory growth over spring is erroneous.

“Yes, they will put on weight but this won’t make up for a loss in frame development.”

He also points out that, unlike sheep and beef farmers, dairy farmers have to work to definitive mating and calving dates.

While sheep and beef finishers can hold onto stock longer before they send them to the processors, dairy farmers can’t delay calving to get heifers to target calving weights.

Both McNeil and Hooper stress they are not blaming graziers for producing underweight heifers, rather they believe all parties need to work together in producing heifers that have met their liveweight targets.

“Too often dairy farmers leave the growing and the rearing of their heifers to the grazier, play no part beyond that and then complain when they get poor results.

“It is a shared responsibility – it’s a business arrangement at the end of the day; it’s about building enduring relationships.”

Hooper urges dairy farmers to take more responsibility with their young stock, whether it is simply viewing a weighing report or physically going to look at the animals.

Hooper stresses the importance of sound grazing contracts as being the basis upon which to build a dairy farmer-grazier relationship.

“The days of the handshakes are pretty much gone.”

Contracts provide graziers with a clear expectation of the end product and the steps along the way.

These are available from organisations such as Dairy NZ and Federated Farmers and can be amended to suit individual arrangements.

Hooper says he would like to see a shift to performance-based contracts where graziers were paid on the quality of the product they produced rather than on a per head basis.

He defines quality as being the number of animals that have met pre-determined target weights.

Weigh to go 

Get them weighed.

Greg McNeil and Jack Hooper stress the need to be regularly weighing heifers to ensure they are meeting target weights.

The information generated from weighing can be used to ensure the heifers are being drenched correctly but most importantly can be used to develop feed and management strategies.

Hooper views weighing as simply monitoring performance, which he says is essential whatever walk of life you are in.

“I think in general if you are not weighing you have lost one of the ways to know how your management is going.”

As a rule of thumb the younger the stock the more often they should be weighed.

So between December and May calves should be weighed frequently, after May they should be weighed every eight-12 weeks or at least four times within their first 18 months.

It is an industry goal to get more animals being weighed on a regular basis so more individual animals are reaching their target weight irrespective of where they are being grazed.

“It’s about knowing what’s happening all the way through an animal’s life, not just at certain stages.” 

Tools of the trade 

MINDA Weights is a tool that provides both dairy farmers and graziers with information on how heifers are performing; whether individually or as a herd they are meeting weight targets.

MINDA is used by about 90% of dairy farmers but the heifer grazing tool can (with the permission of the dairy farmer) be accessed by the grazier.

McNeil says MINDA Weights uses weighing information in a practical way and identifies underperforming animals or animals that are not meeting targets determined by each individual’s genetic make-up.

It also highlights trends over time so seasonal growth-checks can be prevented.

McNeil says the information generated from MINDA Weights can we used to define future management such as filling seasonal shortfalls.

“While the data is produced in real time, it can be reviewed and used a management tool.”

Hooper adds that MINDA Weights needs to be used in conjunction with common sense.

Liveweight BVs are based on an average of the parents of each animal and can be calculated for different ages such as weaning, mating and 22 months.

Targets for individual animals are then combined to form a group target line.

“However, it is important to note this target line is only the average of the group and with the considerable genetic variation that exists between animals, especially crossbreds, it is important that all animals in the group attain their individual target weights.”

One of the challenges for graziers is meeting targets for animals that might be born a month to six weeks apart. MINDA Weights takes that information into account.

LIC genetics consultant Jack Hooper says this is an across the board problem with no single breed being worse than others.

Generally, there are heifer performance targets for every breed and farmers can use data available to identify targets for the animals in their herd.

Each animal is assigned a breeding value (BV) for liveweight relative to 500kg. So if an animal has a target liveweight of 500kg then it has a BV of 0. So if an animal has a liveweight BV of 10 then its target liveweight is 510kg while a liveweight BV of -40 means the cow has a liveweight target of 460kg.

While there is always a variation in the herd, calculating the average of the sum of the individuals will give graziers an idea of the quantity of feed required to meet target weights by the bulk of the herd. 

Plan and talk

Canterbury-based Dairy NZ field officer Kim Reid says dairy farmers, particularly in Canterbury and Southland, rely on off-farm grazing and she says it was important dairy farmers build a good relationship with their graziers.

“The grazier needs to have an understanding of what you are trying to achieve. Have a plan in place and communicate.”

Too many dairy farmers send their stock away and just hope for the best.

She urges farmers to keep a close eye on dairy animals even if they have been assigned to the care of a third party, such as a grazing management service or veterinary practice.

“These arrangements are not bulletproof so out of sight should not be out of mind.”

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